<?php

if (! defined ( 'BASEPATH' ))
	exit ( 'No direct script access allowed' );
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package CodeIgniter
 * @author ExpressionEngine Dev Team
 * @copyright Copyright (c) 2006 - 2011 EllisLab, Inc.
 * @license http://codeigniter.com/user_guide/license.html
 * @link http://codeigniter.com
 * @since Version 2.0
 * @filesource
 *
 */
	
// ------------------------------------------------------------------------

/**
 * CodeIgniter Caching Class
 *
 * @package CodeIgniter
 * @subpackage Libraries
 * @category Core
 * @author ExpressionEngine Dev Team
 * @link
 *
 */
class CI_Cache extends CI_Driver_Library {
	protected $valid_drivers = array (
			'cache_apc',
			'cache_file',
			'cache_memcached',
			'cache_dummy' 
	);
	protected $_cache_path = NULL; // Path of cache files (if file-based cache)
	protected $_adapter = 'dummy';
	protected $_backup_driver;
	
	// ------------------------------------------------------------------------
	
	/**
	 * Constructor
	 *
	 * @param
	 *        	array
	 */
	public function __construct($config = array()) {
		if (! empty ( $config )) {
			$this->_initialize ( $config );
		}
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Get
	 *
	 * Look for a value in the cache. If it exists, return the data
	 * if not, return FALSE
	 *
	 * @param
	 *        	string
	 * @return mixed that is stored/FALSE on failure
	 */
	public function get($id) {
		return $this->{$this->_adapter}->get ( $id );
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Cache Save
	 *
	 * @param
	 *        	string		Unique Key
	 * @param
	 *        	mixed		Data to store
	 * @param
	 *        	int			Length of time (in seconds) to cache the data
	 *        	
	 * @return boolean on success/false on failure
	 */
	public function save($id, $data, $ttl = 60) {
		return $this->{$this->_adapter}->save ( $id, $data, $ttl );
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Delete from Cache
	 *
	 * @param
	 *        	mixed		unique identifier of the item in the cache
	 * @return boolean on success/false on failure
	 */
	public function delete($id) {
		return $this->{$this->_adapter}->delete ( $id );
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Clean the cache
	 *
	 * @return boolean on failure/true on success
	 */
	public function clean() {
		return $this->{$this->_adapter}->clean ();
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Cache Info
	 *
	 * @param
	 *        	string		user/filehits
	 * @return mixed on success, false on failure
	 */
	public function cache_info($type = 'user') {
		return $this->{$this->_adapter}->cache_info ( $type );
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Get Cache Metadata
	 *
	 * @param
	 *        	mixed		key to get cache metadata on
	 * @return mixed value from child method
	 */
	public function get_metadata($id) {
		return $this->{$this->_adapter}->get_metadata ( $id );
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Initialize
	 *
	 * Initialize class properties based on the configuration array.
	 *
	 * @param
	 *        	array
	 * @return void
	 */
	private function _initialize($config) {
		$default_config = array (
				'adapter',
				'memcached' 
		);
		
		foreach ( $default_config as $key ) {
			if (isset ( $config [$key] )) {
				$param = '_' . $key;
				
				$this->{$param} = $config [$key];
			}
		}
		
		if (isset ( $config ['backup'] )) {
			if (in_array ( 'cache_' . $config ['backup'], $this->valid_drivers )) {
				$this->_backup_driver = $config ['backup'];
			}
		}
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * Is the requested driver supported in this environment?
	 *
	 * @param
	 *        	string	The driver to test.
	 * @return array
	 */
	public function is_supported($driver) {
		static $support = array ();
		
		if (! isset ( $support [$driver] )) {
			$support [$driver] = $this->{$driver}->is_supported ();
		}
		
		return $support [$driver];
	}
	
	// ------------------------------------------------------------------------
	
	/**
	 * __get()
	 *
	 * @param
	 *        	child
	 * @return object
	 */
	public function __get($child) {
		$obj = parent::__get ( $child );
		
		if (! $this->is_supported ( $child )) {
			$this->_adapter = $this->_backup_driver;
		}
		
		return $obj;
	}
	
	// ------------------------------------------------------------------------
}
// End Class

/* End of file Cache.php */
/* Location: ./system/libraries/Cache/Cache.php */